Methods for preparing ruthenium carbene complex precursors and ruthenium carbene complexes

ABSTRACT

A method for preparing a ruthenium carbene complex precursor includes reacting a ruthenium refinery salt with a hydrogen halide to form a ruthenium intermediate, and reacting the ruthenium intermediate with an L-type ligand to form the ruthenium carbene complex precursor. A method for preparing a ruthenium vinylcarbene complex includes converting a ruthenium carbene complex precursor into a ruthenium hydrido halide complex, and reacting the ruthenium hydrido halide complex with a propargyl halide to form the ruthenium vinylcarbene complex. A method for preparing a ruthenium carbene complex includes converting a ruthenium carbene complex precursor into a ruthenium carbene complex having a structure (PR 1 R 2 R 3 ) 2 Cl 2 Ru═CH—R 4 , wherein R 1 , R 2 , R 3 , and R 4  are alike or different, and wherein covalent bonds may optionally exist between two or more of R 1 , R 2 , and R 3 .

TECHNICAL FIELD

The present teachings relate generally to ruthenium carbene complexprecursors and preparations thereof, as well as to the use of suchprecursors in the preparation of ruthenium carbene complexes.

BACKGROUND

With the development of new, relatively air-stable transition metalcarbene complex catalysts—particularly ones exhibiting increasedtolerance towards common organic functional groups—the olefin metathesisreaction has established itself as one of the most powerful reactions inthe synthetic preparation of alkenes.

Ruthenium carbene complexes—for example, the “first-generation” and“second generation” Grubbs-type catalysts developed by Nobel laureateRobert H. Grubbs—are especially popular and versatile catalysts for usein olefin metathesis. The polymericdi-μ-chloro(η⁴-1,5-cyclooctadiene)ruthenium(II)—represented herein as[RuCl₂(COD)]_(x)—and the monomeric tris(triphenylphosphine)ruthenium(II)chloride—represented herein as RuCl₂(PPh₃)₃—are precursors in thesynthesis of Grubbs-type ruthenium carbene complexes.

As shown in FIG. 1, [RuCl₂(COD)]_(x) (Inorganic Syntheses, 1989, 29,68-77) and RuCl₂(PPh₃)₃ (Inorganic Syntheses, 1970, 12, 237-240) aretypically prepared starting from RuCl₃.nH₂O. The ruthenium trichlorideis itself prepared starting from low cost ruthenium refinery salts(e.g., ammonium salts of ruthenium-chloro complexes produced in therefining of natural platinum group metal deposits and recycled platinumgroup metals). However, since the ruthenium refinery salts are firstconverted to ruthenium metal, which in turn is then oxidized to Ru(III),the preparations of [RuCl₂(COD)]_(x) and RuCl₂(PPh₃)₃ via theintermediacy of ruthenium trichloride are costly and inefficient.

A more efficient and less costly preparation of [RuCl₂(COD)]_(x),RuCl₂(PPh₃)₃, and analogous MX₂L_(q) ruthenium carbene complexprecursors from ruthenium refinery salts—particularly one that does notrequire the intermediacy of ruthenium trichloride—is desirable.

SUMMARY

The scope of the present invention is defined solely by the appendedclaims, and is not affected to any degree by the statements within thissummary.

By way of introduction, a first method for preparing a ruthenium carbenecomplex precursor in accordance with the present teachings includes (a)reacting a ruthenium refinery salt with a hydrogen halide to form aruthenium intermediate, and (b) reacting the ruthenium intermediate withan L-type ligand to form the ruthenium carbene complex precursor.

A second method for preparing a ruthenium carbene complex precursor inaccordance with the present teachings includes (a) reacting a rutheniumrefinery salt with a hydrogen halide to form a ruthenium intermediate,and (b) reacting the ruthenium intermediate with cyclooctadiene and/or aphosphorous-containing material having a structure PR¹R²R³ to form theruthenium carbene complex precursor. The ruthenium refinery saltincludes a material selected from the group consisting of (NH₄)₂RuCl₅,(NH₄)₂RuCl₅.H₂O, polyhydrated (NH₄)₂RuCl₅, (NH₄)₄[Ru₂OCl₁₀], andcombinations thereof. The ruthenium intermediate includes a compoundselected from the group consisting of (NH₄)₂RuX¹ ₆, (NH₄)₂RuX¹ _(y)X²_(6-y), wherein y is an integer value from 1 to 5, and a combinationthereof. The ruthenium carbene complex precursor includes a compoundhaving a structure [RuX³X⁴(COD)]_(x), wherein x is an integer value of 1or more, and/or a compound having a structure RuX⁵X⁶(PR¹R²R³)₃, whereinR¹, R², and R³ are alike or different and are each independentlyselected from the group consisting of substituted or unsubstituted aryl,substituted or unsubstituted C₁-C₁₀ alkyl, substituted or unsubstitutedaryloxy, substituted or unsubstituted C₁-C₁₀ alkoxy, and combinationsthereof. Covalent bonds may optionally exist between two or more of R¹,R², and R³, such that when two or more of R¹, R², and R³ are takentogether, a bidentate ligand to phosphorous is formed. X¹, X², X³, X⁴,X⁵, and X⁶ are halogen atoms that are each independently selected fromthe group consisting of F, Cl, Br, and I with a caveat that X¹ and X²are different.

A first method for preparing a ruthenium vinylcarbene complex inaccordance with the present teachings includes (a) converting aruthenium carbene complex precursor prepared according to a methoddescribed above into a ruthenium hydrido halide complex, and (b)reacting the ruthenium hydrido halide complex with a propargyl halide toform the ruthenium vinylcarbene complex.

A method for preparing a ruthenium carbene complex in accordance withthe present teachings includes converting a ruthenium carbene complexprecursor prepared according to a method described above into aruthenium carbene complex having a structure (PR¹R²R³)₂X¹X²Ru═CH—R⁴. X¹and X² are halogen atoms that are each independently selected from thegroup consisting of F, Cl, Br, and I. R¹, R², R³, and R⁴ are alike ordifferent, and are each independently selected from the group consistingof substituted or unsubstituted aryl, substituted or unsubstitutedC₁-C₁₀ alkyl, substituted or unsubstituted aryloxy, substituted orunsubstituted C₁-C₁₀ alkoxy, and combinations thereof. Covalent bondsmay optionally exist between two or more of R¹, R², and R³, such thatwhen two or more of R¹, R², and R³ are taken together, a bidentateligand to phosphorous is formed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a synthetic scheme for converting ruthenium refinery saltsto [RuCl₂(COD)]_(x) and RuCl₂(PPh₃)₃ by conventional methodologies.

FIG. 2 shows a synthetic scheme for converting ruthenium refinery saltsto [RuCl₂(COD)]_(x) in accordance with the present teachings.

FIG. 3 shows a synthetic scheme for converting the ruthenium carbenecomplex precursor [RuCl₂(COD)]_(x) to a Grubbs-type olefin metathesiscatalyst.

FIG. 4 shows a synthetic scheme for converting ruthenium refinery saltsto RuCl₂(PPh₃)₃ in accordance with the present teachings.

FIG. 5 shows a synthetic scheme for converting the ruthenium carbenecomplex precursor RuCl₂(PPh₃)₃ to a Grubbs-type olefin metathesiscatalyst.

FIG. 6 shows the infrared spectra of [RuCl₂(COD)]_(x) prepared inaccordance with the present teachings (top spectrum) and commerciallyavailable [RuCl₂(COD)]_(x) purchased from Strem Chemicals, Inc. (bottomspectrum).

DETAILED DESCRIPTION

A facile synthetic route to ruthenium carbene complex metathesiscatalyst precursors—such as [RuCl₂(COD)]_(x), RuCl₂(PPh₃)₃, andanalogous MX₂L_(q) complexes (e.g., where q is an integer from 1 through4)—has been discovered and is described herein. As shown in FIGS. 2 and4, the inventive route starts from low-cost ruthenium refinery salts anddoes not require any conversion of these salts to ruthenium metal orsubsequent oxidation of ruthenium metal to RuCl₃—two of the principaldrawbacks associated with the conventional synthetic preparations ofRuCl₂(COD)]_(x), RuCl₂(PPh₃)₃, and analogous complexes.

Definitions

Throughout this description and in the appended claims, the followingdefinitions are to be understood:

The phrase “ruthenium refinery salt” refers generally to a ruthenium-and halogen-containing material. It is to be understood that a“ruthenium refinery salt” as defined herein may further compriseadditional elements besides ruthenium and halogen, including but notlimited to oxygen. Representative examples of “ruthenium refinery salts”include but are not limited to materials obtained from—or substantiallychemically equivalent to what could otherwise be obtained from—theprocessing of a natural platinum group metal (PGM) deposit, as well asmaterials obtained from alternative chemical sources (e.g., ammoniatedruthenium oxychloride aka ruthenium red, etc.) and/or from recoveryand/or reclamation processing of a ruthenium-containing material used ina prior chemical reaction. In some embodiments, a “ruthenium refinerysalt” is obtained from a natural PGM deposit by a technique as describedin Reactive & Functional Polymers, 2005, 65, 205-217.

The phrase “ruthenium intermediate” refers to a ruthenium-containingmaterial that is obtained from but is chemically different than aruthenium refinery salt that was subjected to a reaction involving ahydrogen halide.

The phrase “L-type ligand” refers to a two-electron neutral ligand.Representative examples of an “L-type ligand” for use in accordance withthe present teachings include but are not limited to olefins,phosphines, phosphites, amines, carbon monoxide (CO), nitrogen (N₂), andthe like, and combinations thereof.

The term “olefin” refers to a hydrocarbon compound containing at leastone carbon-carbon double bond. As used herein, the term “olefin”encompasses straight, branched, and/or cyclic hydrocarbons having onlyone carbon-carbon double bond (e.g., monoenes) as well as more than onecarbon-carbon double bond (e.g., dienes, trienes, etc.). In someembodiments, the olefin is functionalized.

The term “functionalized” as used in reference to an olefin refers tothe presence of one or more heteroatoms, wherein the heteroatom is anatom other than carbon and hydrogen. In some embodiments, the heteroatomconstitutes one atom of a polyatomic functional group withrepresentative functional groups including but not limited to carboxylicacids, carboxylic esters, ketones, aldehydes, anhydrides,sulfur-containing groups, phosphorous-containing groups, amides, imides,N-containing heterocycles, aromatic N-containing heterocycles, saltsthereof, and the like, and combinations thereof.

The term “hydrothermal” used in connection with reactions, conversions,treatments, and the like refers to reaction conditions within asubstantially “closed” reaction system—typically though not necessarilya system in which pressure and/or temperature exceed atmosphericconditions—such as may be achieved in a Parr-type reactor.

The term “atmospheric” used in connection with reactions, conversions,treatments, and the like refers to reaction conditions within an “open”(as opposed to closed) reaction system. It is to be understood that“atmospheric” in the sense used herein does not preclude theintroduction into a reaction vessel of an inert atmosphere (e.g., ablanket of an inert gas) to replace or exclude air. Moreover, it is tobe further understood that in an open reaction system, an internaltemperature and/or pressure within the reaction vessel may exceed theambient temperature and/or pressure outside the reaction vessel (inother words, “atmospheric” as used herein is not necessarily synonymouswith “ambient” although, in some embodiments, it may be).

It is to be understood that elements and features of the variousrepresentative embodiments described below may be combined in differentways to produce new embodiments that likewise fall within the scope ofthe present teachings.

By way of general introduction, a method for preparing a rutheniumcarbene complex precursor in accordance with the present teachingscomprises reacting a ruthenium refinery salt with a hydrogen halide toform a ruthenium intermediate, and reacting the ruthenium intermediatewith an L-type ligand to form the ruthenium carbene complex precursor.

In some embodiments, the hydrogen halide is provided as a gas. In someembodiments, the hydrogen halide is provided in solution. In someembodiments, the hydrogen halide is provided as an aqueous solution. Insome embodiments, the hydrogen halide is selected from the groupconsisting of hydrogen chloride, hydrogen bromide, hydrogen fluoride,hydrogen iodide, and combinations thereof. In some embodiments, thehydrogen halide is selected from the group consisting of hydrogenchloride, hydrogen bromide, hydrogen iodide, and combinations thereof.In some embodiments, the hydrogen halide is selected from the groupconsisting of hydrogen chloride, hydrogen bromide, and a combinationthereof. In some embodiments, the hydrogen halide comprises hydrogenchloride. In some embodiments, the hydrogen halide comprises an aqueoussolution of hydrogen chloride (e.g., hydrochloric acid). In someembodiments, the hydrogen halide comprises hydrogen bromide. In someembodiments, the hydrogen halide comprises an aqueous solution ofhydrogen bromide (e.g., hydrobromic acid).

In some embodiments, the L-type ligand is selected from the groupconsisting of olefins, phosphines, phosphites, amines, CO, N₂, andcombinations thereof. In some embodiments, the L-type ligand is selectedfrom the group consisting of olefins, phosphines, and a combinationthereof.

In some embodiments, the L-type ligand comprises an olefin. In someembodiments, the olefin is selected from the group consisting ofmonoenes, dienes, trienes, and combinations thereof. In someembodiments, the olefin is acyclic. In some embodiments, the olefincomprises an acyclic C6 or greater monoene. In some embodiments, theolefin comprises an acyclic diene with representative acyclic dienesincluding but not limited to 1,5-hexadiene, 2,6-octadiene, and the like,and combinations thereof. In some embodiments, the olefin is cyclic. Insome embodiments, the olefin comprises a cyclic diene withrepresentative cyclic dienes including but not limited tocyclohexadiene, cycloheptadiene, cyclooctadiene, cyclononadiene,cyclodecadiene, cycloundecadiene, cyclododecadiene, paramenthadiene,phellandrene, norbornadiene, terpinene, limonene, and the like, andcombinations thereof. In some embodiments, the olefin comprises anacyclic triene. In some embodiments, the olefin comprises a cyclictriene with a representative cyclic triene including but not limited tocyclododecatriene. In some embodiments, the olefin is aromatic withrepresentative aromatic olefins including but not limited tocyclopentadiene, benzene, toluene, o-xylene, m-xylene, p-xylene,mesitylene, and the like, and combinations thereof.

In some embodiments, the L-type ligand comprises aphosphorous-containing ligand (e.g., phosphines, phosphites, and thelike, and combinations thereof). In some embodiments, thephosphorous-containing ligand comprises a structure PR¹R²R³, wherein R¹,R², and R³ are alike or different and are each independently selectedfrom the group consisting of substituted or unsubstituted aryl,substituted or unsubstituted C₁-C₁₀ alkyl, substituted or unsubstitutedaryloxy, substituted or unsubstituted C₁-C₁₀ alkoxy, and combinationsthereof. In some embodiments, covalent bonds may optionally existbetween two or more of R¹, R², and R³, such that when two or more of R¹,R², and R³ are taken together, a bidentate ligand to phosphorous isformed. In some embodiments, the phosphorous-containing ligand comprisesa phosphine. In some embodiments, the phosphine comprises a trialkylphosphine. In some embodiments, the phosphine comprises triphenylphosphine. In some embodiments, the phosphorous-containing ligandcomprises a phosphite.

The chemical composition of a particular ruthenium refinery salt for usein accordance with the present teachings can differ according to thespecific refinery that produced it and/or the exact methodology used bythat refinery in procuring the ruthenium from a natural PGM deposit.Moreover, it is to be understood that a ruthenium refinery salt inaccordance with the present teachings can include one or moreimpurities—including but not limited to Ru metal, NH₄Cl, and the like,and combinations thereof—that are either removed, either partially orcompletely, prior to reacting the ruthenium refinery salt with hydrogenhalide, or else carried along, either in whole or in part, for thereaction with hydrogen halide. For embodiments in which one or moreimpurity (e.g., Ru metal, NH₄Cl, etc.) is not completely removed fromthe ruthenium refinery salt prior to reacting the ruthenium refinerysalt with hydrogen halide, at least a portion of the one or moreimpurity may be carried over into the resultant ruthenium intermediatewhich, in some embodiments, may itself be further contaminated by thepresence of unreacted starting material (e.g., (NH₄)₄[Ru₂OCl₁₀], etc.).In such instances, the one or more impurity and/or unreacted startingmaterial can be removed, either partially or completely, prior toreacting the ruthenium intermediate with an L-type ligand to form theruthenium carbene complex precursor or else carried along, either inwhole or in part, for the reaction with an L-type ligand.

In some embodiments, a ruthenium refinery salt in accordance with thepresent teachings comprises one or a plurality of halide ligands and/orone or a plurality of ammonium cations. In some embodiments, a rutheniumrefinery salt in accordance with the present teachings comprises one ora plurality of chloride ligands and/or one or a plurality of ammoniumcations. In some embodiments, a ruthenium refinery salt for use inaccordance with the present teachings is one produced by Refinery A. Insome embodiments, the ruthenium refinery salt is one produced byRefinery B. In some embodiments, the ruthenium refinery salt is acombination of a material produced by Refinery A and a material producedby Refinery B.

As further described in Examples 1 and 2 below, x-ray powder diffraction(XRD) analysis of representative ruthenium refinery salts purchased,respectively, from Refinery A and Refinery B was performed. The XRDanalysis of a representative ruthenium refinery salt obtained fromRefinery B revealed the following composition: (NH₄)₄[Ru₂OCl₁₀] (36.4 wt%), (NH₄)₂RuCl₅.H₂O (13.9 wt %), and NH₄Cl (49.3 wt %). By contrast tothe large weight percentage of NH₄Cl impurity identified in the RefineryB sample, an XRD analysis of a representative ruthenium refinery saltobtained from Refinery A revealed the following composition:(NH₄)₄[Ru₂OCl₁₀] (96.1 wt %) and Ru metal impurity (3.9 wt %).

In some embodiments, a ruthenium refinery salt for use in accordancewith the present teachings comprises a material selected from the groupconsisting of (NH₄)₂RuCl₅, (NH₄)₂RuCl₅.H₂O, polyhydrated (NH₄)₂RuCl₅,(NH₄)₄[Ru₂OCl₁₀], and combinations thereof. In some embodiments, aruthenium refinery salt for use in accordance with the present teachingscomprises (NH₄)₄[Ru₂OCl₁₀]. In some embodiments, the ruthenium refinerysalt further comprises an NH₄Cl impurity which, in some embodiments, isresidual reagent left over from a ruthenium recovery process (e.g., whenNH₄Cl is added to solution to precipitate pentachloro rutheniumspecies).

In some embodiments, the method in accordance with the present teachingsfurther comprises removing at least a portion of the excess NH₄Cl (ifpresent) from the ruthenium refinery salt prior to reacting theruthenium refinery salt with the hydrogen halide. Although pre-removalof excess NH₄Cl is not essential, in some embodiments it is desirableinasmuch as higher yields are generally achievable when excess NH₄Cl hasbeen removed. In some embodiments, at least a portion of the NH₄Climpurity is removed via sublimation. In some embodiments, at least aportion of sublimed NH₄Cl is removed from the remaining rutheniumrefinery salt prior to reacting the remaining ruthenium refinery saltwith the hydrogen halide.

In some embodiments, the ruthenium refinery salt used in accordance withthe present teachings is a Refinery A sample inasmuch as it does notcontain a significant amount of NH₄Cl impurity that would warrant theextra step of its removal. It is to be understood that while the methodsdescribed herein have been demonstrated using ruthenium refinery saltsfrom two different refineries—Refinery A and Refinery B—the presentteachings can also be applied to ruthenium refinery salts from otherrefineries as well without limitation.

In some embodiments, the reacting of a ruthenium refinery salt with ahydrogen halide to form a ruthenium intermediate comprises ahydrothermal treatment. In some embodiments, the reacting is performedin a closed system. In some embodiments, a reaction temperature in theclosed system is at least about 100° C. In some embodiments, a reactiontemperature in the closed system is at least about 120° C. In someembodiments, a reaction temperature in the closed system is at leastabout 130° C. In some embodiments, a reaction temperature in the closedsystem is at least about 140° C. In some embodiments, a reactiontemperature in the closed system is at least about 150° C. In someembodiments, a reaction temperature in the closed system is at leastabout 160° C. In some embodiments, a reaction temperature in the closedsystem is at least about 170° C. In some embodiments, a reactiontemperature in the closed system is at least about 175° C. In someembodiments, a reaction temperature in the closed system is at leastabout 180° C.

Although the use of a gaseous hydrogen halide has been contemplated forsome embodiments of the present teachings (for both hydrothermal andatmospheric conversions of ruthenium refinery salt to rutheniumintermediate), it is presently believed that the use of gaseous reagentmay be less practical and/or slower than the use of a correspondingliquid acid reagent. Thus, in some embodiments, the hydrogen halide isprovided in solution. In some embodiments, the hydrogen halide isprovided in an aqueous solution.

In some embodiments, the hydrogen halide comprises hydrogen chloridewhich, in some embodiments, is provided in aqueous solution ashydrochloric acid. In some embodiments, the hydrochloric acid has aconcentration of at least about 3 M or higher. In some embodiments, thehydrochloric acid has a concentration of at least about 4 M or higher.In some embodiments, the hydrochloric acid has a concentration of atleast about 5 M or higher. In some embodiments, the hydrochloric acidhas a concentration of at least about 6 M or higher. In someembodiments, the hydrochloric acid has a concentration of at least about7 M or higher. In some embodiments, the hydrochloric acid has aconcentration of at least about 8 M or higher. In some embodiments, thehydrochloric acid has a concentration of at least about 9 M or higher.In some embodiments, the hydrochloric acid is concentrated hydrochloricacid.

In some embodiments, the hydrogen halide comprises hydrogen bromidewhich, in some embodiments, is provided in aqueous solution ashydrobromic acid. In some embodiments, the ruthenium intermediate formedby reacting a ruthenium refinery salt with hydrogen bromide comprisesone or a plurality of ammonium cations and/or one or a plurality ofbromide ligands. In some embodiments, the ruthenium intermediatecomprises a compound having a structure (NH₄)₂RuBr₆. In someembodiments, the ruthenium intermediate comprises a compound having astructure (NH₄)₂RuBr₆ and/or (NH₄)₂RuCl_(z)Br_(6-z), where z is aninteger from 1 to 5.

While neither desiring to be bound by any particular theory norintending to limit in any measure the scope of the appended claims ortheir equivalents, it is presently believed that the yield of thehydrothermal reaction by which ruthenium refinery salt is converted toruthenium intermediate increases with increasing concentration of theacid (e.g., hydrochloric acid). In addition, in view of the watersolubility of the ruthenium intermediate, it is presently believed thatthe yield can be improved by washing the solid ruthenium intermediateproduct with an organic solvent instead of water. Representative organicsolvents for use in accordance with the present teachings include butare not limited to aliphatic hydrocarbons (e.g., pentane, hexane,heptane, cyclohexane, etc.), esters (e.g., diethyl acetate, etc.),ketones (e.g., acetone, etc.), alcohols (e.g., methanol, ethanol,iso-propyl alcohol, etc.), aromatic hydrocarbons (e.g., benzene,toluene, xylenes, etc.), halogenated aromatic hydrocarbons (e.g.,chlorobenzene, dichlorobenzene, etc.), halogenated alkanes (e.g.,dichloromethane, chloroform, dichloroethane, etc.), ethers (e.g.,dioxane, tetrahydrofuran, diethyl ether, tert-butyl methyl ether,dimethoxyethane, etc.), and the like, and combinations thereof. In someembodiments, the organic solvent used to wash the solid rutheniumintermediate product is cooled below room temperature prior to beingused for the washing. In some embodiments, the organic solvent comprisesacetone.

In some embodiments, the ruthenium refinery salt is one that is obtainedfrom Refinery A, which was predetermined by XRD analysis to containabout 96.1 wt % (NH₄)₄[Ru₂OCl₁₀] and about 3.9 wt % Ru metal impurity.In some embodiments, the Refinery A ruthenium refinery salt is convertedto a ruthenium intermediate comprising (NH₄)₂RuCl₆—which, in someembodiments, appears as black crystals—via a hydrothermal treatment(150° C., 9 M HCl, 1.5 h) in yields of about 90 to about 95 percent(with about 4% of byproduct recovered by weight).

In some embodiments, the ruthenium refinery salt is one that is obtainedfrom Refinery B, which was predetermined by XRD analysis to containabout 36.4 wt % (NH₄)₄[Ru₂OCl₁₀], about 13.9 wt % (NH₄)₂RuCl₅.H₂O, andabout 49.3 wt % NH₄Cl impurity. In some embodiments, excess NH₄Cl (about40 wt %) is first removed from the Refinery B ruthenium refinery saltvia sublimation. In some embodiments, the Refinery B ruthenium refinerysalt remaining after sublimation is converted to a rutheniumintermediate comprising (NH₄)₂RuCl₆—which, in some embodiments, appearsas black crystals—via a hydrothermal treatment (150° C., 9 M HCl, 2 h)in yields of about 82 to about 95 percent.

In some embodiments, the reacting of a ruthenium refinery salt withhydrogen halide to form a ruthenium intermediate comprises atmosphericconditions. In some embodiments, the reacting is performed in an opensystem. In some embodiments, the reacting is performed in an open systemand the hydrogen halide is provided as an aqueous solution. In someembodiments, the hydrogen halide comprises hydrogen chloride, which insome embodiments is provided in aqueous solution as hydrochloric acid.In some embodiments, the hydrogen chloride is provided in aqueoussolution as concentrated hydrochloric acid. In some embodiments, thehydrochloric acid has a concentration of at least about 6 M or higher.In some embodiments, the hydrochloric acid has a concentration of atleast about 7 M or higher. In some embodiments, the hydrochloric acidhas a concentration of at least about 8 M or higher. In someembodiments, the hydrochloric acid has a concentration of at least about9 M or higher. In some embodiments, the reacting comprises refluxing theruthenium refinery salt in concentrated hydrochloric acid. In someembodiments, the hydrogen halide comprises hydrogen bromide, which insome embodiments is provided in aqueous solution as hydrobromic acid. Insome embodiments, the reacting comprises refluxing the rutheniumrefinery salt in concentrated hydrobromic acid.

In some embodiments, the reacting under atmospheric conditions comprisesrefluxing the ruthenium refinery salt in an aqueous solution of ahydrogen halide. In some embodiments, the reacting under atmosphericconditions comprises refluxing the ruthenium refinery salt inhydrochloric acid (e.g., 7 M, 8 M, 9 M or concentrated) for at least 5hours, in some embodiments for at least 6 hours, and in some embodimentsfor at least 7 or more hours. In some embodiments, the rutheniumintermediate obtained by the atmospheric synthesis is a black solid.However, the ruthenium intermediate product produced under atmosphericconditions does not always appear to be black. In some embodiments, theyields of ruthenium intermediate obtained by atmospheric synthesis areabout 80 to about 90 percent.

Either atmospheric or hydrothermal conditions can be used for theconversion of a ruthenium refinery salt to a ruthenium intermediate inaccordance with the present teachings. In some embodiments, hydrothermalconditions may be desirable (e.g., to increase reproducibility of theconversion). In some embodiments, atmospheric conditions may bedesirable (e.g., in larger scale reactions for which an appropriatelysized Parr-type reactor is not readily available).

In some embodiments, the ruthenium intermediate formed from the reactionof a ruthenium refinery salt with hydrogen halide comprises one or aplurality of ammonium cations and/or one or a plurality of halideligands. In some embodiments, the hydrogen halide comprises hydrogenchloride, and the ruthenium intermediate formed from the reaction of aruthenium refinery salt with hydrogen chloride comprises one or aplurality of ammonium cations and/or one or a plurality of chlorideligands. In some embodiments, the ruthenium intermediate furthercomprises one or a plurality of additional halide ligands other thanchloride. In some embodiments, the ruthenium intermediate comprises acompound selected from the group consisting of (NH₄)₂RuCl₆, (NH₄)₃RuCl₆,(NH₄)₂RuCl₅.H₂O, (NH₃)₆RuCl₃, (NH₄)₂RuBr₆, (NH₄)₂RuCl_(z)Br_(6-z),wherein z is an integer from 1 to 5, and combinations thereof.

In some embodiments, the ruthenium intermediate comprises a compoundselected from the group consisting of (NH₄)₂RuCl₆, (NH₄)₂RuBr₆,(NH₄)₂RuCl_(z)Br_(6-z), wherein z is an integer from 1 to 5, andcombinations thereof. In some embodiments, the ruthenium intermediatecomprises a compound having a structure (NH₄)₂RuCl₆. In someembodiments, at least a portion of the (NH₄)₂RuCl₆ is crystalline. Inother embodiments, at least a portion of the (NH₄)₂RuCl₆ is a powder. Insome embodiments, the (NH₄)₂RuCl₆ appears as black microcrystals. Whileneither desiring to be bound by any particular theory nor intending tolimit in any measure the scope of the appended claims or theirequivalents, it is presently believed that at least a portion of the(NH₄)₂RuCl₆ is crystalline when it has been prepared according tohydrothermal conditions, whereas at least a portion of the (NH₄)₂RuCl₆is a powder when it has been prepared according to atmosphericconditions.

As further described in Example 12 below, samples of rutheniumintermediates obtained from the hydrothermal and atmospheric treatmentsof a ruthenium refinery salt with hydrochloric acid were examined by XRDanalysis and were found to be comprised primarily of (NH₄)₂RuCl₆.Depending on the conditions under which the ruthenium intermediate wasformed, the samples were found to contain varying amounts of impuritiesincluding (NH₄)₄[Ru₂OCl₁₀] and Ru metal.

In some embodiments, the ruthenium intermediate obtained from thehydrothermal and/or atmospheric treatment of a ruthenium refinery saltin accordance with the present teachings is reacted with an olefin toform a ruthenium carbene complex precursor. In some embodiments, theolefin is cyclic. In some embodiments, the cyclic olefin is selectedfrom the group consisting of cyclohexadiene, cycloheptadiene,cyclooctadiene, cyclononadiene, cyclodecadiene, cycloundecadiene,cyclododecadiene, cyclododecatriene, all stereoisomers thereof, and thelike, and combinations thereof. In some embodiments, the cyclic olefinis selected from the group consisting of cyclooctadiene,cyclododecatriene, and combinations thereof.

In some embodiments, about two equivalents of a cyclic olefin arereacted with a ruthenium intermediate to form a ruthenium carbenecomplex precursor in accordance with the present teachings. In someembodiments, about two equivalents of cyclooctadiene are reacted with aruthenium intermediate to form a ruthenium carbene complex precursor inaccordance with the present teachings. In some embodiments, the olefin(e.g., cyclooctadiene) is reacted with the ruthenium intermediate in analcoholic solvent which, in some embodiments, can further serve as areducing agent. Representative alcoholic solvents include but are notlimited to aliphatic alcohols (e.g., methanol, ethanol, 1-propanol,iso-propanol, 1-butanol, sec-butanol, and the like, and combinationsthereof), aromatic alcohols, polyols, and the like, and combinationsthereof. In some embodiments, the cyclooctadiene reacted with theruthenium intermediate comprises cis, cis-1,5-cyclooctadiene. In someembodiments, the ruthenium intermediate comprises (NH₄)₂RuCl₆, thecyclooctadiene comprises cis, cis-1,5-cyclooctadiene, and the reactingcomprises refluxing the (NH₄)₂RuCl₆ and cis, cis-1,5-cyclooctadiene inan aliphatic alcoholic solvent. In some embodiments, the reaction of theruthenium intermediate with cis, cis-1,5-cyclooctadiene to form aruthenium carbene complex precursor is conducted in ethanol. In someembodiments, the yield of the reaction is higher in ethanol than inbutanol, methanol or iso-propanol.

In some embodiments, a ruthenium intermediate (NH₄)₂RuCl₆ prepared underhydrothermal conditions is reacted with cyclooctadiene to form aruthenium carbene complex precursor. In other embodiments, a rutheniumintermediate (NH₄)₂RuCl₆ prepared under atmospheric conditions isreacted with cyclooctadiene to form a ruthenium carbene complexprecursor. While neither desiring to be bound by any particular theorynor intending to limit in any measure the scope of the appended claimsor their equivalents, it is presently observed that (a) the yield ofruthenium carbene complex precursor from the reaction of rutheniumintermediate with cyclooctadiene increases (e.g., from about 33% toabout 62%) as reaction time increases (e.g., from about 7 hours to about30 hours), (b) the yield of the ruthenium carbene complex precursor doesnot change significantly when the amount of cyclooctadiene is increasedfrom 2 equivalents to 3 equivalents, (c) using a ruthenium intermediate(NH₄)₂RuCl₆ prepared under hydrothermal conditions yields the sameruthenium carbene complex precursor as does using a rutheniumintermediate (NH₄)₂RuCl₆ prepared under atmospheric conditions, and (d)the reaction between ruthenium intermediate and cyclooctadiene proceedsto the same yield regardless of whether it is conducted in air or in anitrogen atmosphere.

In some embodiments, as shown in FIG. 3, the ruthenium carbene complexprecursor comprises a material having a structure [RuCl₂(COD)]_(x),wherein x is an integer value of 1 or more. In some embodiments, the[RuCl₂(COD)]_(x) is polymeric. In some embodiments, the [RuCl₂(COD)]_(x)appears as a yellowish-brownish solid.

In some embodiments, as shown in FIG. 3, a method for preparing aruthenium vinylcarbene complex comprises converting a ruthenium carbenecomplex precursor prepared in accordance with the present teachings intoa ruthenium hydrido halide complex, and reacting the ruthenium hydridohalide complex with a propargyl halide to form the rutheniumvinylcarbene complex. In some embodiments, the vinylcarbene complexconstitutes a first-generation Grubbs-type olefin metathesis catalyst.In some embodiments, as shown in FIG. 3, the converting of the rutheniumcarbene complex precursor into the ruthenium hydrido halide complexcomprises reacting the ruthenium carbene complex precursor with atrialkyl phosphine, hydrogen, and a trialkyl amine as described, forexample, in Organometallics, 1997, 16, No. 18, 3867-3869.

In some embodiments, the ruthenium hydrido halide complex comprises acompound having a structure [Ru(H)(H₂)X(PR¹R²R³)₂], wherein X is ahalide and wherein R¹, R², and R³ are alike or different and are eachindependently selected from the group consisting of substituted orunsubstituted aryl, substituted or unsubstituted C₁-C₁₀ alkyl,substituted or unsubstituted aryloxy, substituted or unsubstitutedC₁-C₁₀ alkoxy, and combinations thereof. In some embodiments, covalentbonds may optionally exist between two or more of R¹, R², and R³, suchthat when two or more of R¹, R², and R³ are taken together, a bidentateligand to phosphorous is formed. In some embodiments, the C₁-C₁₀ alkylgroup is primary alkyl, secondary alkyl or cycloalkyl. In someembodiments, the cycloalkyl is cyclohexyl (Cy). In some embodiments, theruthenium hydrido halide complex comprises a compound having a structure[Ru(H)(H₂)Cl(PCy₃)₂]. In some embodiments, the propargyl halidecomprises 3-chloro-3-methyl-1-butyne. In some embodiments, as shown inFIG. 3, the ruthenium vinylcarbene complex prepared from the rutheniumcarbene complex precursor comprises a compound having a structure(PCy₃)₂Cl₂Ru═CH—CH═C(CH₃)₂.

In some embodiments, the above-described method for preparing aruthenium vinylcarbene complex further comprises replacing aphosphorous-containing ligand of the ruthenium vinylcarbene complex[Ru(H)(H₂)X(PR¹R²R³)₂] with an N-heterocyclic carbene ligand asdescribed, for example, in U.S. Pat. No. 7,329,758 B1. In someembodiments, a phosphorous-containing ligand of the rutheniumvinylcarbene complex (e.g., a trialkyl phosphine ligand) is replacedwith an imidazolidine ligand to form an imidazolidine-containingruthenium vinylcarbene complex. In some embodiments, as shown in FIG. 3,the imidazolidine ligand comprises 1,3-dimesityl-4,5-dihydroimidazole.In some embodiments, the imidazolidine-containing ruthenium vinylcarbenecomplex constitutes a second-generation Grubbs-type olefin metathesiscatalyst.

In some embodiments, the ruthenium intermediate obtained from thehydrothermal and/or atmospheric treatment of a ruthenium refinery saltin accordance with the present teachings is reacted with aphosphorous-containing material (e.g., a phosphine and/or phosphite) toform a ruthenium carbene complex precursor. In some embodiments, thephosphorous-containing material comprises a structure PR¹R²R³, whereinR¹, R², and R³ are alike or different and are each independentlyselected from the group consisting of substituted or unsubstituted aryl,substituted or unsubstituted C₁-C₁₀ alkyl, substituted or unsubstitutedaryloxy, substituted or unsubstituted C₁-C₁₀ alkoxy, and combinationsthereof. In some embodiments, covalent bonds may optionally existbetween two or more of R¹, R², and R³, such that when two or more of R¹,R², and R³ are taken together, a bidentate ligand to phosphorous isformed. In some embodiments, one or more of R¹, R², and R³ comprisesphenyl. In some embodiments, each of R¹, R², and R³ comprises phenyl. Insome embodiments, one or more of R¹, R², and R³ comprises cycloalkyl(e.g., cyclohexyl). In some embodiments, each of R¹, R², and R³comprises cycloalkyl (e.g., cyclohexyl). In some embodiments, theruthenium intermediate obtained from the hydrothermal and/or atmospherictreatment of a ruthenium refinery salt with hydrogen chloride inaccordance with the present teachings is reacted with three equivalentsof a phosphorous-containing material (e.g., a phosphine) to form aruthenium carbene complex precursor comprising a structureRuCl₂(PR¹R²R³)₃, wherein R¹, R², and R³ are alike or different and areeach independently selected from the group consisting of substituted orunsubstituted aryl, substituted or unsubstituted C₁-C₁₀ alkyl,substituted or unsubstituted aryloxy, substituted or unsubstitutedC₁-C₁₀ alkoxy, and combinations thereof. In some embodiments, covalentbonds may optionally exist between two or more of R¹, R², and R³, suchthat when two or more of R¹, R², and R³ are taken together, a bidentateligand to phosphorous is formed.

In some embodiments, as shown in FIG. 5, a method for preparing aruthenium carbene complex comprises converting a ruthenium carbenecomplex precursor prepared in accordance with the present teachings intoa ruthenium carbene complex having a structure (PR¹R²R³)₂Cl₂Ru═CH—R⁴,wherein R¹, R², R³, and R⁴ are alike or different, and are eachindependently selected from the group consisting of substituted orunsubstituted aryl, substituted or unsubstituted C₁-C₁₀ alkyl,substituted or unsubstituted aryloxy, substituted or unsubstitutedC₁-C₁₀ alkoxy, and combinations thereof. In some embodiments, covalentbonds may optionally exist between two or more of R¹,R², and R³, suchthat when two or more of R¹,R², and R³ are taken together, a bidentateligand to phosphorous is formed. In some embodiments, one or more of R¹,R², R³, and R⁴ comprises phenyl. In some embodiments, each of R¹, R²,R³, and R⁴ comprises phenyl. In some embodiments, one or more of R¹, R²,R³, and R⁴ comprises cycloalkyl (e.g., cyclohexyl). In some embodiments,each of R¹, R², R³, and R⁴ comprises cycloalkyl (e.g., cyclohexyl). Insome embodiments, the carbene complex constitutes a first-generationGrubbs-type olefin metathesis catalyst. In some embodiments, as shown inFIG. 5, the converting of the ruthenium carbene complex precursor into aruthenium carbene complex comprises reacting the ruthenium carbenecomplex precursor with phenyldiazomethane as described, for example, inJ. Am. Chem. Soc., 1996, 118, 100.

In some embodiments, as shown in FIG. 5, the above-described method forpreparing a ruthenium carbene complex further comprises replacing aphosphorous-containing ligand of the ruthenium carbene complex (e.g., aphosphine) with an N-heterocyclic carbene ligand to form anN-heterocyclic carbene-containing ruthenium carbene complex. In someembodiments, a phosphorous-containing ligand of the ruthenium carbenecomplex is replaced with an imidazolidine ligand to form animidazolidine-containing ruthenium carbene complex. In some embodiments,as shown in FIG. 5, the imidazolidine ligand comprises1,3-dimesityl-4,5-dihydroimidazole. In some embodiments, theimidazolidine-containing ruthenium carbene complex constitutes asecond-generation Grubbs-type olefin metathesis catalyst.

By way of illustration, as shown in FIGS. 3 and 5, ruthenium carbenecomplex precursurs such as [RuCl₂(COD)]_(x) and RuCl₂(PPh₃)₃ prepared inaccordance with the present teachings can be readily transformed intoruthenium carbene complexes for use as olefin metathesis catalysts(e.g., first- and/or second-generation Grubbs-type metathesiscatalysts). Moreover, in contrast to conventional methodology, thepresent teachings circumvent costly conversions of ruthenium refinerysalts to ruthenium metal and subsequent oxidation of ruthenium metal toRuCl₃. In addition, the present teachings are in no way limited to theruthenium feedstock from a particular refinery, and salts from otherrefineries in addition to the A and B refineries referenced herein maybe employed.

The following examples and representative procedures illustrate featuresin accordance with the present teachings, and are provided solely by wayof illustration. They are not intended to limit the scope of theappended claims or their equivalents.

EXAMPLES

Materials

Unless otherwise indicated, all chemicals were used as received andwithout drying. Ruthenium refinery salt was purchased from Refineries Aand B. Ethanol (200 proof, absolute), hydrochloric acid (37%),hydrobromic acid (48%), and cis,cis-1,5-cyclooctadiene (>98% pure) werepurchased from Sigma Aldrich.

Example 1 XRD Analysis of Refinery A Ruthenium Refinery Salt

A sample of a Refinery A ruthenium refinery salt was examined by XRDanalysis as received. The x-ray powder patterns were measured (Cu K_(α)radiation, 5-100° 2θ, 0.0202144° steps, 1 sec/step) on a Bruker D2Phaser diffractometer equipped with a LynxEye position-sensitivedetector. Quantitative analysis of the crystalline phases was carriedout by the Rietveld method using GSAS.

The Refinery A ruthenium refinery salt was determined to contain(NH₄)₄[Ru₂OCl₁₀] and 3.9(1) wt % Ru metal impurity. The compound wasidentified by indexing the pattern on a high-quality body-centeredtetragonal unit cell, and using lattice matching techniques to find theK analog (Acta Cryst. B, 1979, 35, 558-561). The structure was refined,as shown in Table 1, and hydrogens placed in approximate positions. Anacceptable Rietvald refinement was obtained.

TABLE 1 Refined Atom Coordinates of (NH₄)₄[Cl₅RuORuCl₅] Space Group = l4/m m m Lattice constants are a = 7.30369(11); b = A; c = 17.0938(4);Alpha = 90; Beta = 90; Gamma = 90; Cell volume = 911.850(28) Name X Y ZUi/Ue*100 Site sym Mult Type Seq Fractn Ru1 0.000000 0.0000000.10779(18) 2.14 4MM(001) 4 RU 1 1.0000 Cl2 0.22958(28) 0.22958(28)0.11396(26) 2.12 M(+−0) 16 CL 2 1.0000 Cl3 0.000000 0.000000 0.24535(44)2.12 4MM(001) 4 CL 3 1.0000 O4 0.000000 0.000000 0.000000 3.00 4/MMM0012 O 4 1.0000 N5 0.000000 0.500000 0.250000 3.00 −4M2 001 4 N 5 1.0000 N60.000000 0.500000 0.000000 3.00 MMM 4 N 6 1.0000 H7 0.056070 0.4339800.216790 5.00 1 32 H 7 0.5000 H8 0.060210 0.557780 0.029880 5.00 1 32 H8 0.5000

Example 2 XRD Analysis of Refinery B Ruthenium Refinery Salt

A sample of Refinery B ruthenium refinery salt was first ground with amortar and pestle prior to analysis but an acceptable powder pattern wasnot obtained from the damp solid. A portion was ground as an acetoneslurry with a mortar and pestle, which resulted in a better powderpattern. The x-ray powder patterns were measured (Cu K_(α) radiation,5-100° 2θ, 0.0202144° steps, 1 sec/step) on a Bruker D2 Phaserdiffractometer equipped with a LynxEye position-sensitive detector.Quantitative analysis of the crystalline phases was carried out by theRietveld method using GSAS.

The Refinery B ruthenium refinery salt was determined to contain amixture of 36.4(2) wt % (NH₄)₄[Ru₂OCl₁₀], 49.6(2) wt % NH₄Cl, and13.9(2) wt % (NH₄)₂RuCl₅.H₂0. The (NH₄)₄[Ru₂OCl₁₀] exhibits significantpreferred orientation (texture index=2.02, reflecting difficulty ingrinding the large grains to obtain a random powder. The (NH₄)₂RuCl₅.H₂0was identified by analogy to several (NH₄)₂RuCl₅X compounds. At present,the powder pattern is not yet in the Powder Diffraction File but thecrystal structure has been reported (Zh. Strukt. Khim., 2008, 49,585-588; ICSD collection code 411727). The (NH₄)₄[Ru₂OCl₁₀] in theRefinery B sample exhibits a larger degree of strain broadening than theRefinery A sample.

The phase composition for the Refinery B salt corresponds to a bulkanalysis of C_(0.0)H_(32.51)N_(8.00)O_(0.63)Ru_(1.0)Cl_(11.00) comparedto the measured C_(0.09)H_(19.68)N_(5.20)O_(1.30)Ru_(1.0)Cl_(8.43).While neither desiring to be bound by any particular theory norintending to limit in any measure the scope of the appended claims ortheir equivalents, it is presently believed that the preferredorientation/granularity may have distorted the quantitative analysisand/or that the sample contains some amorphous material.

Example 3 Removal of NH₄Cl from Refiner B Ruthenium Refine Salt bySublimation

In a sublimator, 7.5 g of Refinery B ruthenium salt was sublimed invacuo (0.05 Torr), at 150-200° C. for 6 hours. NH₄Cl sublimes onto thecold finger (−5° C.) (2.2 g) while the Ru salts remain below (4.3 g).Ruthenium salt remaining after sublimation is determined to be(NH₄)₄[Ru₂OCl₁₀] and (NH₄)₂RuCl₅.H₂O by elemental analysis and IRspectroscopy. Ru wt %=32.9% up from 18.8% in raw salt.

Example 4 Hydrothermal Treatment of Sublimed Refinery B RutheniumRefinery Salt

In a 23-mL Parr reactor, sublimed Refinery B ruthenium refinery salt(1.0660 g) and 6 M HCl (10 mL) were heated to 150° C. for 6 hours. Theresulting solution was filtered at room temperature and blackmicrocrystals remained on the filter paper. The microcrystals werewashed with water. Elemental analysis confirmed that the blackmicrocrystalline product was (NH₄)₂RuCl₆ (0.63 g).

Example 5 Preparation of Ruthenium Carbene Complex Precursor[RuCl₂(COD)]_(x) from Refinery B-Derived Ruthenium Intermediate

In a 200-mL 3-necked flask fitted with an inlet, a condenser, a bubbler,and a stopper, (NH₄)₂RuCl₆ (1.57 g, product from hydrothermal treatmentof a Refinery B salt), cis,cis-1,5-cyclooctadiene (1.48 g, 3 eq.), andethanol (45 mL) were refluxed for 6 hours under N₂. The solid wasinsoluble in ethanol; however, there was a color change from black torusty brown. The solid was filtered at ambient temperature through aBuchner funnel and washed with ethanol. The isolated rusty brown solidwas then washed with H₂O (100 mL) yielding a yellowish brown solid,[RuCl₂(COD)]_(x) (0.2126 g).

Example 6 Hydrothermal Treatment of Refinery A Ruthenium Refinery Salt

In a 23-mL Parr reactor, Refinery A ruthenium refinery salt (1 g) and 6M HCl (10 mL) were heated to 150° C. for 6 hours. The resulting solutionwas filtered at room temperature and black microcrystals remained on thefilter paper. The microcrystals were washed with water. Elementalanalysis confirmed that the black microcrystalline product was(NH₄)₂RuCl₆ (0.6 g).

Example 7 Hydrothermal Treatment of Refinery A Ruthenium Refinery Salt

In a 23-mL Parr reactor, Refinery A ruthenium refinery salt (1 g) and 9M HCl (5 mL) were heated to 150° C. for 2 hours. The resulting solutionwas filtered at room temperature and black microcrystals remained on thefilter paper. The microcrystals were washed with acetone. Elementalanalysis confirmed that the black microcrystalline product was(NH₄)₂RuCl₆ (1.1 g).

Example 8 Atmospheric Treatment of Refinery A Ruthenium Refinery Salt

In a 100-mL round-bottomed flask fitted with a condenser, Refinery Aruthenium refinery salt (3.0302 g) and concentrated HCl (37%, 30 mL)were refluxed at 100° C. for 6 hours. The resulting solution wasfiltered at room temperature in a Buchner funnel, and a fine blacksolid, (NH₄)₂RuCl₆ (2.5118 g) was washed with water and recovered fromthe filter paper.

Example 9 Atmospheric Treatment of Refinery A Ruthenium Refinery Salt

In a 200-mL 3-necked flask fitted with N₂ purge and a condenser,Refinery A ruthenium refinery salt (5 g) and concentrated HBr (50 mL)were refluxed for 6 h. A bluish-black solid (7.6 g) was filtered out ofthe solution at room temperature using a Buchner funnel and washed withacetone. Elemental analysis confirmed that a majority of the solidproduct is (NH₄)₂RuBr₆ (yield about 80%) with about 1.2 wt % chlorinepresent. The chlorine may stem from (NH₄)₂RuCl_(z)Br_(6-z), where z isan integer from 1 to 5, and/or from unreacted (NH₄)₄[Ru₂OCl₁₀] startingmaterial present in the sample.

Example 10 Preparation of Ruthenium Carbene Complex Precursor[RuCl₂(COD)]_(x) from Refinery A-Derived Ruthenium Intermediate

In a 200-mL 3-necked flask fitted with an inlet, a condenser, a bubbler,and a stopper, (NH₄)₂RuCl₆ (1.13 g, product from hydrothermal treatmentof a Refinery A salt), cis,cis-1,5-cyclooctadiene (1.05 g, 3 eq.), andethanol (30 mL) were refluxed for 6 hours under N₂. The solid wasinsoluble in ethanol; however, there was a color change from black torusty brown. The solid was filtered at ambient temperature through aBuchner funnel and washed with ethanol. The isolated rusty brown solidwas then washed with H₂O (100 mL) yielding a yellowish brown solid,[RuCl₂(COD)]_(x) (0.2977 g).

As shown in FIG. 6, the IR spectrum of synthesized [RuCl₂(COD)]_(x) (topspectrum) prepared from a Refinery A salt as described above matchesthat of commercially available [RuCl₂(COD)]_(x) from Strem Chemicals,Inc. (Newburyport, Mass.) (bottom spectrum). Moreover, an equivalentproduct is obtained when the [RuCl₂(COD)]_(x) is prepared from RefineryB salt (after its purification via sublimation). Thus, a viablesynthesis of [RuCl₂(COD)]_(x)—a precursor to ruthenium carbenecomplexes, such as those used as catalysts in olefin metathesis—fromlow-cost ruthenium refinery salts via the intermediacy of (NH₄)₂RuCl₆has been demonstrated.

Example 11 Preparation of Ruthenium Carbene Complex Precursor[RuCl₂(COD)]_(x) from Refinery A-Derived Ruthenium Intermediate

In a 200-mL 3-necked flask fitted with an inlet, a condenser, a bubbler,and a stopper, (NH₄)₂RuCl₆ (3.03 g, product from hydrothermal treatmentof a Refinery A salt), cis,cis-1,5-cyclooctadiene (1.96 g, 2 eq.), andethanol (45 mL) were refluxed for 30 hours under N₂. The solid wasinsoluble in ethanol; however, there was a color change from black torusty brown. The solid was filtered at ambient temperature through aBuchner funnel and washed with ethanol. The isolated rusty brown solidwas then washed with H₂O (250 mL) yielding a yellowish brown solid,[RuCl₂(COD)]_(x) (1.56 g).

Example 12 XRD Analysis of Ruthenium Intermediates Obtained fromHydrothermal and Atmospheric Treatments of Refinery A Ruthenium RefinerySalt

A sample of a ruthenium intermediate obtained from the atmospherictreatment of a Refinery A refinery salt was examined by XRD analysis asreceived. A sample of a ruthenium intermediate obtained from thehydrothermal treatment of a Refinery A ruthenium refinery salt wasground with a mortar and pestle prior to analysis.

The x-ray powder patterns were measured (Cu K_(α) radiation, 5-100° 2θ,0.0202144° steps, 0.5 sec/step) on a Bruker D2 Phaser diffractometerequipped with a LynxEye position-sensitive detector. Quantitativeanalysis of the crystalline phases was carried out by the Rietveldmethod using GSAS.

The x-ray powder pattern of the major phase in both samples matches thatof several face-centered cubic (NH₄)₂MCl₆ compounds. Accordingly, thisphase was identified as (NH₄)₂RuCl₆. Since the crystal structure of(NH₄)₂RuCl₆ was not previously refined, although some of itsthermodynamic properties have been reported in the literature (J. ChemThermodynamics, 2002, 34, 133-153), the structure of (NH₄)₂ReCl₆ wasused as the initial model for the refinement, as shown in Table 3.

TABLE 3 Refined Crystal Structure of (NH₄)₂RuCl₆ Space Group = Fm3m, a =9.86201 (13) Å ATOM x y z U_(iso), Å² Ru1 0 0 0 0.0241(7) Cl2 0.2361(2)0 0 0.0255(8) N3 ¼ ¼ ¼ 0.03  H4 0.3072 0.3072 0.3072 0.039

The displacement coefficient of the Cl is reasonable for afully-occupied chlorine atom. Therefore, the compound is identified as(NH₄)₂RuCl₆ rather than (NH₄)₂RuCl₅.H₂O, which would yield a largerU_(iso) for the Cl.

The phase composition data for the two samples are shown in Table 4.Both samples are comprised primarily of (NH₄)₂RuCl₆ but contain varyingamounts of impurities including (NH₄)₄[Ru₂OCl₁₀] and Ru metal. Thehydrothermally-derived ruthenium intermediate has a lower concentrationof impurities and was contains 94.3 wt % (NH₄)₂RuCl₆, 0.9 wt %(NH₄)₄[Ru₂OCl₁₀], and 4.9 wt % Ru metal. The atmospherically-derivedruthenium intermediate appears to have some amorphous material (from abroad feature in the background at approximately 16° 2θ), and contains83.5 wt % (NH₄)₂RuCl₆, 10 wt % (NH₄)₄[Ru₂OCl₁₀], and 6.4 wt % Ru metal.

TABLE 4 Phase Compositions of Ruthenium Intermediate SamplesHydrothermally- Atmospherically- Derived Ruthenium Derived RutheniumIntermediate Intermediate (NH₄)₂RuCl₆, wt % 94.3 (1) 83.5 (1) a, Å9.8637 (2) 9.8620 (1) Profile U 17.2 (49) 51 (3) Profile Y 16.4 (4) 4.8(4) strain, % 0.25 (1) 0.05 (1) (NH₄)₄[Ru₂OCl₁₀], wt % 0.9 (1) 10.0 (1)Ru, wt % 4.9 (1) 6.4 (1) Profile X 5.8 (3) 6.3 (2) size, Å 2500 (200)2200 (100) other amorphous

The entire contents of each and every patent and non-patent publicationcited herein are hereby incorporated by reference, except that in theevent of any inconsistent disclosure or definition from the presentspecification, the disclosure or definition herein shall be deemed toprevail.

The foregoing detailed description and accompanying drawings have beenprovided by way of explanation and illustration, and are not intended tolimit the scope of the appended claims. Many variations in the presentlypreferred embodiments illustrated herein will be apparent to one ofordinary skill in the art, and remain within the scope of the appendedclaims and their equivalents.

It is to be understood that the elements and features recited in theappended claims may be combined in different ways to produce new claimsthat likewise fall within the scope of the present invention. Thus,whereas the dependent claims appended below depend from only a singleindependent or dependent claim, it is to be understood that thesedependent claims can, alternatively, be made to depend in thealternative from any preceding claim—whether independent ordependent—and that such new combinations are to be understood as forminga part of the present specification.

The invention claimed is:
 1. A method for preparing a ruthenium carbenecomplex precursor comprising: (a) reacting a ruthenium refinery saltwith a hydrogen halide to form a ruthenium intermediate, the rutheniumrefinery salt being a salt of a halogen-containing ruthenium complex;wherein the hydrogen halide comprises hydrogen chloride, hydrogenbromide, or combinations thereof; and wherein the halogen-containingruthenium complex comprises halogen atoms selected from the groupconsisting of chlorine and bromine; and (b) reacting the rutheniumintermediate with an L-type ligand to form the ruthenium carbene complexprecursor.
 2. The invention of claim 1 wherein the L-type ligand isselected from the group consisting of olefins, phosphines, phosphites,amines, CO, N₂, and combinations thereof.
 3. The invention of claim 1wherein the L-type ligand is selected from the group consisting ofolefins, phosphines, and a combination thereof.
 4. The invention ofclaim 1 wherein the L-type ligand comprises a cyclic olefin.
 5. Theinvention of claim 4 wherein the cyclic olefin is selected from thegroup consisting of a diene, a triene, and a combination thereof.
 6. Theinvention of claim 4 wherein the cyclic olefin is selected from thegroup consisting of cyclohexadiene, cycloheptadiene, cyclooctadiene,cyclononadiene, cyclodecadiene, cycloundecadiene, cyclododecadiene,cyclododecatriene, paramenthadiene, phellandrene, norbornadiene,terpinene, limonene, and combinations thereof.
 7. The invention of claim4 wherein the cyclic olefin is selected from the group consisting ofcyclooctadiene, cyclododecatriene, and combinations thereof.
 8. Theinvention of claim 4 wherein the cyclic olefin comprises cyclooctadiene.9. The invention of claim 1 wherein the L-type ligand comprises aphosphorous-containing ligand having a structure PR¹R²R³; wherein R¹,R², and R³ are alike or different and are each independently selectedfrom the group consisting of substituted or unsubstituted aryl,substituted or unsubstituted C₁-C₁₀ alkyl, substituted or unsubstitutedaryloxy, substituted or unsubstituted C₁-C₁₀ alkoxy, and combinationsthereof; and wherein covalent bonds may optionally exist between two ormore of R¹, R², and R³, such that when two or more of R¹, R², and R³ aretaken together, a bidentate ligand to phosphorous is formed.
 10. Theinvention of claim 9 wherein the phosphorous-containing ligand comprisestriphenyl phosphine.
 11. The invention of claim 1 wherein the hydrogenhalide comprises hydrogen chloride.
 12. The invention of claim 1 whereinthe hydrogen halide comprises hydrogen bromide.
 13. The invention ofclaim 1 wherein the hydrogen halide comprises hydrogen chloride andwherein the L-type ligand comprises a cyclic olefin.
 14. The inventionof claim 13 wherein the cyclic olefin comprises cyclooctadiene.
 15. Theinvention of claim 1 wherein the ruthenium refinery salt comprises amaterial selected from the group consisting of (NH₄)₂RuCl₅,(NH₄)₂RuCl₅.H₂O, polyhydrated (NH₄)₂RuCl₅, (NH₄)₄[Ru₂OCl₁₀], andcombinations thereof.
 16. The invention of claim 15 wherein theruthenium refinery salt further comprises NH₄Cl.
 17. The invention ofclaim 16 wherein the method further comprises removing at least aportion of the NH₄Cl from the ruthenium refinery salt prior to reactingthe ruthenium refinery salt with the hydrogen halide.
 18. The inventionof claim 17 wherein at least a portion of the NH₄Cl is removed viasublimation.
 19. The invention of claim 18 wherein at least a portion ofsublimed NH₄Cl is removed from the ruthenium refinery salt prior toreacting the ruthenium refinery salt with the hydrogen halide.
 20. Theinvention of claim 1 wherein the ruthenium intermediate comprises one ora plurality of ammonium cations and one or a plurality of halideligands, the halide ligands being selected from the group consisting ofchloride and bromide.
 21. The invention of claim 1 wherein the rutheniumintermediate comprises one or a plurality of ammonium cations and one ora plurality of chloride ligands.
 22. The invention of claim 21 whereinthe ruthenium intermediate further comprises one or a plurality ofbromide ligands.
 23. The invention of claim 1 wherein the rutheniumintermediate comprises a compound having a structure (NH₄)₂RuCl₆. 24.The invention of claim 23 wherein at least a portion of the (NH₄)₂RuCl₆is crystalline.
 25. The invention of claim 23 wherein at least a portionof the (NH₄)₂RuCl₆ is a powder.
 26. The invention of claim 11 whereinthe hydrogen chloride is provided in aqueous solution as hydrochloricacid.
 27. The invention of claim 26 wherein concentration of thehydrochloric acid is at least about 5 M or higher.
 28. The invention ofclaim 26 wherein concentration of the hydrochloric acid is at leastabout 6 M or higher.
 29. The invention of claim 6 wherein the reactingwith the hydrogen halide comprises a hydrothermal treatment.
 30. Theinvention of claim 23 wherein the hydrogen halide comprise hydrogenchloride, which is provided in aqueous solution as hydrochloric acidhaving a concentration of at least about 6 M, and wherein the reactingis performed in a closed system.
 31. The invention of claim 30 wherein areaction temperature in the closed system is at least about 100° C. 32.The invention of claim 31 wherein at least a portion of the (NH₄)₂RuCl₆is crystalline.
 33. The invention of claim 6 wherein the reacting withthe hydrogen halide comprises atmospheric conditions.
 34. The inventionof claim 33 wherein the hydrogen halide comprises hydrogen chloride,which is provided in aqueous solution as concentrated hydrochloric acid,and wherein the reacting is performed in an open system.
 35. Theinvention of claim 34 wherein the ruthenium refinery salt is refluxed inthe concentrated hydrochloric acid.
 36. The invention of claim 35wherein the ruthenium intermediate comprises a compound having astructure (NH₄)₂RuCl₆, and wherein at least a portion of the (NH₄)₂RuCl₆is a powder.
 37. The invention of claim 14 wherein the rutheniumintermediate comprises a compound having a structure (NH₄)₂RuCl₆, andwherein the cyclooctadiene comprises cis, cis-1,5-cyclooctadiene. 38.The invention of claim 14 wherein the ruthenium intermediate comprises acompound having a structure (NH₄)₂RuCl₆, and wherein the reacting of theruthenium intermediate with cyclooctadiene comprises refluxing theruthenium intermediate and cis, cis-1,5-cyclooctadiene in ethanol. 39.The invention of claim 1 wherein the ruthenium carbene complex precursorcomprises a material having a structure [RuCl₂(COD)]_(x), wherein x isan integer value of 1 or more.
 40. The invention of claim 1 wherein theruthenium carbene complex precursor comprises a material having astructure RuCl₂(PR¹R²R³)₃; wherein R¹, R², and R³ are alike or differentand are each independently selected from the group consisting ofsubstituted or unsubstituted aryl, substituted or unsubstituted C₁-C₁₀alkyl, substituted or unsubstituted aryloxy, substituted orunsubstituted C₁-C₁₀ alkoxy, and combinations thereof; and whereincovalent bonds may optionally exist between two or more of R¹, R², andR³, such that when two or more of R¹, R², and R³ are taken together, abidentate ligand to phosphorous is formed.
 41. A method for preparing aruthenium carbene complex precursor comprising: reacting a rutheniumrefinery salt with a hydrogen halide to form a ruthenium intermediate;and reacting the ruthenium intermediate with cyclooctadiene and/or aphosphorous-containing material having a structure PR¹R²R³ to form theruthenium carbene complex precursor; wherein the ruthenium refinery saltcomprises a material selected from the group consisting of (NH₄)₂RuCl₅,(NH₄)₂RuCl₅.H₂O, polyhydrated (NH₄)₂RuCl₅, (NH₄)₄[Ru₂OCl₁₀], andcombinations thereof; wherein the ruthenium intermediate comprises acompound selected from the group consisting of (NH₄)₂RuX¹ ₆, (NH₄)₂RuX¹_(y)X² _(6-y), and a combination thereof; wherein the ruthenium carbenecomplex precursor comprises a compound having a structure[RuX³X⁴(COD)]_(x) and/or a compound having a structure RuX⁵X⁶(PR¹R²R³)₃;wherein x is an integer value of 1 or more; wherein X¹, X², X³, X⁴, X⁵,and X⁶ are halogen atoms that are each independently selected from thegroup consisting of F, Cl, Br, and I with a caveat that X¹ and X² aredifferent; wherein y is an integer value from 1 to 5; wherein R¹, R²,and R³ are alike or different and are each independently selected fromthe group consisting of substituted or unsubstituted aryl, substitutedor unsubstituted C₁-C₁₀ alkyl, substituted or unsubstituted aryloxy,substituted or unsubstituted C₁-C₁₀ alkoxy, and combinations thereof;and wherein covalent bonds may optionally exist between two or more ofR¹, R², and R³, such that when two or more of R¹, R², and R³ are takentogether, a bidentate ligand to phosphorous is formed.
 42. A method forpreparing a ruthenium vinylcarbene complex comprising: converting aruthenium carbene complex precursor prepared according to the method ofclaim 4 into a ruthenium hydrido halide complex; and reacting theruthenium hydrido halide complex with a propargyl halide to form theruthenium vinylcarbene complex.
 43. The invention of claim 42 whereinthe converting comprises reacting the ruthenium carbene complexprecursor with a trialkyl phosphine, hydrogen, and a trialkyl amine. 44.The invention of claim 42 wherein the ruthenium hydrido halide complexcomprises a compound having a structure [Ru(H)(H₂)X(PR¹R²R³)₂]; whereinX is a halide; wherein R¹, R², and R³ are alike or different and areeach independently selected from the group consisting of substituted orunsubstituted aryl, substituted or unsubstituted C₁-C₁₀ alkyl,substituted or unsubstituted aryloxy, substituted or unsubstitutedC₁-C₁₀ alkoxy, and combinations thereof; and wherein covalent bonds mayoptionally exist between two or more of R¹, R², and R³, such that whentwo or more of R¹, R², and R³ are taken together, a bidentate ligand tophosphorous is formed.
 45. The invention of claim 42 wherein theruthenium hydrido halide complex comprises a compound having a structure[Ru(H)(H₂)Cl(PCy₃)₂], and wherein the propargyl halide comprises3-chloro-3-methyl-1-butyne.
 46. The invention of claim 45 wherein theruthenium vinylcarbene complex comprises a compound having a structure(PCy₃)₂Cl₂Ru═CH—CH═C(CH₃)₂.
 47. The invention of claim 43 furthercomprising replacing a phosphine ligand of the ruthenium vinylcarbenecomplex with an N-heterocyclic carbene ligand.
 48. The invention ofclaim 43 further comprising replacing a phosphine ligand of theruthenium vinylcarbene complex with an imidazolidine ligand to form animidazolidine-containing ruthenium vinylcarbene complex.
 49. Theinvention of claim 48 wherein the imidazolidine-containing rutheniumvinylcarbene complex constitutes a second-generation Grubbs-type olefinmetathesis catalyst.
 50. The invention of claim 48 wherein theimidazolidine ligand comprises 1,3-dimesityl-4,5-dihydroimidazole.
 51. Amethod for preparing a ruthenium carbene complex comprising: convertinga ruthenium carbene complex precursor prepared according to the methodof claim 9 into a ruthenium carbene complex having a structure(PR¹R²R³)₂X¹X²Ru═CH—R⁴; wherein X¹ and X² are halogen atoms that areeach independently selected from the group consisting of Cl and Br;wherein R¹, R², R³, and R⁴ are alike or different, and are eachindependently selected from the group consisting of substituted orunsubstituted aryl, substituted or unsubstituted C₁-C₁₀ alkyl,substituted or unsubstituted aryloxy, substituted or unsubstitutedC₁-C₁₀ alkoxy, and combinations thereof; and wherein covalent bonds mayoptionally exist between two or more of R¹, R², and R³, such that whentwo or more of R¹, R², and R³ are taken together, a bidentate ligand tophosphorous is formed.
 52. The invention of claim 51 wherein theruthenium carbene complex precursor comprises a structureRuCl₂(PR¹R²R³)₃.
 53. The invention of claim 51 wherein each of R¹, R²,R³, and R⁴ comprises phenyl.
 54. The invention of claim 51 wherein theconverting comprises reacting the ruthenium carbene complex precursorwith phenyldiazomethane.
 55. The invention of claim 51 furthercomprising replacing a phosphorous-containing ligand of the rutheniumcarbene complex with an N-heterocyclic carbene ligand to form anN-heterocyclic carbene-containing ruthenium carbene complex.
 56. Theinvention of claim 51 further comprising replacing aphosphorous-containing ligand of the ruthenium carbene complex with animidazolidine ligand to form an imidazolidine-containing rutheniumcarbene complex.
 57. A method for preparing a ruthenium complexcomprising reacting a ruthenium refinery salt with a hydrogen halide toform the ruthenium complex, the ruthenium refinery salt being a salt ofa halogen-containing ruthenium complex; wherein the hydrogen halidecomprises hydrogen chloride, hydrogen bromide, or combinations thereof;and wherein the halogen-containing ruthenium complex comprises halogenatoms selected from the group consisting of chlorine and bromine. 58.The invention of claim 57 wherein the ruthenium complex comprises an[RuX¹ _(y)X² _(6-y)]²⁻ anion, wherein X¹ and X² are halogen atoms thatare each independently selected from the group consisting of Cl and Br,and wherein y is an integer value from 1 to
 6. 59. The invention ofclaim 57 wherein the ruthenium complex comprises one or a plurality ofammonium cations and one or a plurality of halide ligands, the halideligands being selected from the group consisting of chloride andbromide.
 60. The invention of claim 57 wherein the ruthenium complexcomprises one or a plurality of ammonium cations and one or a pluralityof chloride ligands.
 61. The invention of claim 57 wherein the rutheniumcomplex comprises a compound selected from the group consisting of(NH₄)₂RuX¹ ₆, (NH₄)₂RuX¹ _(y)X² _(6-y), and a combination thereof;wherein X¹ and X² are halogen atoms that are each independently selectedfrom the group consisting of Cl and Br; and wherein y is an integervalue from 1 to
 5. 62. The invention of claim 57 wherein the rutheniumcomplex comprises a compound selected from the group consisting of(NH₄)₂RuCl₆, (NH₄)₂RuBr₆, (NH₄)₂RuCl₂Br_(6-z) wherein z is an integerfrom 1 to 5, and combinations thereof.
 63. The invention of claim 57wherein the hydrogen halide comprises hydrogen chloride.
 64. Theinvention of claim 57 wherein the hydrogen halide comprises hydrogenbromide.
 65. The invention of claim 57 wherein the ruthenium refinerysalt comprises a material selected from the group consisting of(NH₄)₂RuCl₅, (NH₄)₂RuCl₅.H₂O, polyhydrated (NH₄)₂RuCl₅,(NH₄)₄[Ru₂OCl₁₀], and combinations thereof.
 66. The invention of claim65 wherein the hydrogen chloride is provided in aqueous solution ashydrochloric acid.
 67. The invention of claim 57 wherein the reactingwith the hydrogen halide comprises a hydrothermal treatment.
 68. Theinvention of claim 57 wherein the reacting with the hydrogen halidecomprises atmospheric conditions.
 69. The invention of claim 1 whereinthe L-type ligand is selected from the group consisting of olefins,phosphines, and a combination thereof.
 70. The invention of claim 1wherein the L-type ligand comprises a cyclic olefin.
 71. The inventionof claim 70 wherein the cyclic olefin is selected from the groupconsisting of a diene, a triene, and a combination thereof.
 72. Theinvention of claim 70 wherein the cyclic olefin is selected from thegroup consisting of cyclohexadiene, cycloheptadiene, cyclooctadiene,cyclononadiene, cyclodecadiene, cycloundecadiene, cyclododecadiene,cyclododecatriene, paramenthadiene, phellandrene, norbornadiene,terpinene, limonene, and combinations thereof.
 73. The invention ofclaim 70 wherein the cyclic olefin is selected from the group consistingof cyclooctadiene, cyclododecatriene, and combinations thereof.
 74. Theinvention of claim 70 wherein the cyclic olefin comprises1,5-cyclooctadiene.
 75. The invention of claim 1 wherein the rutheniumintermediate is a ruthenium (IV) hexahalo complex that comprises a [RuX¹_(y)X² _(6-y)]²⁻ anion, wherein X¹ and X² are halogen atoms that areindependently selected from the group consisting of Cl and Br; andwherein y is an integer value from 1 to
 6. 76. The invention of claim 75wherein the L-type ligand is selected from the group consisting ofolefins, phosphines, phosphites, amines, CO, N₂, and combinationsthereof.
 77. The invention of claim 1, wherein the rutheniumintermediate is a salt of a ruthenium (IV) hexahalo complex, wherein thehalide ligands of the ruthenium (IV) hexahalo complex are selected fromthe group consisting of chloride and bromide.
 78. The invention of claim77, wherein the L-type ligand is selected from the group consisting ofolefins, phosphines, phosphites, amines, CO, N₂, and combinationsthereof.